Dynamo-electric machine



Sept. 28 1926. 1,601,125 G. H. LELAND DYNAMO ELECTRI C MACHINE Filed Oct. 5, 1921 Patented Sept. 28, 1926.

UNITED STATES PATENT OFFICE.

GEORGE E. LELAND, OF DAYTON, OHIO, ASSIGNOR OF ONE-HALF TO THE LELAND ELECTRIC COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

DYNLHO-ELECTBIG MACHINE.

Application filed October 5, 1921. Serial No. 505,454.

This invention relates to improvements in dynamo electric machines, having particular reference to single-phase alternating current motors of the repulsion-starting and induction-running type, andbeing a modification of the improvements which form the subject matter of m& copending application for patent Serial 0. 425,832, filed November 22, 1920.

In my earlier invention, above referred to, the improvements consist essentially in providing a centrifu al element mounted in operative relation with the armature shaft to effect short-circuiting of the armature when the motor attains o crating speed, the centrifugal element, in tlie preferred form illustrated, consistin in a plurality of weights operable radially outwardly of the armature shaft into contact with the commutator segments, thus to form the shortcircuit, and operable radially toward the shaft to disi'u t the short-circuit when the motor falls be ow operating speed. An important feature of the invention which forms the subject matter of my earlier application consists in providing means for causing 'a"Wi'plI1" action of the weight elements, with increasing pressure on the 'contact surfaces as contact is made-thug to ob-' tain and maintain highly eflicient conditions of the motor in its adaptability to change from repulsion to induction operation.

The present invention provides means, as

a further step, for maintaining these highly desirable conditions ofoperation in motors of this type, the improvements of the invention consisting in means for retaining the weight elements radially aligned one with another,thus to insure under all conditions the full wiping, pressure relat on between the contact elements as the short-circuit is made or broken.

It is an object of the present invention to retain the simple construction and direct relation of parts, which are of outstanding merit in my invention of record referred to, and to adapt the present improvements to the earlier construction without material change in the arrangement of parts or their coordinated operation,-the whole purpose of the later modification being, as stated, to insure normal action of the short-circuitingelements without chance or possibility of inefiicient operation.

In the accompanying drawings:

Fig. 1 is a detail view of a motor having my invention applied thereto, and showing the commutator and short-circuiting mechanism in section, taken on line 11 of Fig. 2;

Fig. 2 is a full end view of Fig. 1 having part of the mechanism broken away;

Fig. 3 is in two detail sectional views illustrating the short-circuiting elements in operative and inoperative relations;

Fig. 4 is in two detail views illustrating the weight elements detached, and

Fig. 5 is a diagrammatic view illustrating the direction of forces operative in the short-circuiting operation and in effecting the wiping, pressure contact action of the elements.

As here shown, the details of motor construction used for illustrating the invention consist of the armature shaft -1, rotor -2, commutator ring -3 and commutator segments -4, these parts being common to motors of the type illustrated and adapted in any suitable form for the practice of my invention.

The short-circuiting mechanism, as here shown, consists of a plurality of wedgeshaped weights arran ed around the commutator shaft between flat, radial weights 6 which serve to'divide the weights 5 into 'groups,there being, as here shown, six roups of weights with nine weights 5 and one weight 6 "to each group. The weights are retained in their radial "relation on shaft 1 by a coiled spring 7 which is arranged circumferentially around the assembled weights and acting, when the motor is at rest, to hold the weights in contact at their inner ends with shaft --1, the weights and spring -7 being retained outward axial displacement relative to shaft 1 by a disc -8 and spring lockring 9 set in an annular groove 10 of the shaft, disc 8 being otherwise free to rotate on the shaft, thus compensating for the rotating momentum of the weights and effecting smooth operation of the motor.

As best shown in Fig. 2 of the drawings, retaining disc 8 has a series of radial slots 11, and each weight -6 has a shoulder --12 adapted to fit freely in one of the slots -11, the slot thus acting as a guide for the weight in its radial movements and acting to prevent rotative or lateral movement of weights 6 relative to the disc, and also to reduce lateral movement of weights to such extent that lateral displacement of weights will be negligible and the best 5 contact relations between the weights and the commutator segments will be maintained.

As best shown in Fig. 3 weights -5 and 6 are each provided with a lower inward projection 13 which has free sliding relation in a depression -14: in the outer face of the commutator ring 3, and an upper inward projection 15 which has sliding contact relation with the commutator seg- 15 ments 4; under inward, lateral pressure 99 spring at the contact points 15 of the weights will be inwardly at an angle to the radial plane of operation of the weights, with the result that contact between the weights and commutator segments will be made by wiping action of the weights under increasing pressure as the weights move outwardly under centrifugal force generated therein by rotation of the motor, the direction of forces being indicated in Fig. 5, and

as will be readily understood from the detailed description, the weights being equally grouped and retained in approximate radial planes, the short-circuiting contact will be made between each weight and segment without variation as to the relative movement 'therebetween, or variations so slight that the elfect on the operation of the motor will be negligible.

Motors embodying my invention in the" earlier construction of record herein re ferred to, have proved in tests to be highly efficient and are being manufactured in quantities, and tests made of the present invention show results which evidence the utmost dependability and effectiveness of the short circuiting mechanism.-

Having described my invention, I claim:

1. In short-circuiting mechanism for single-phase, alternating current motors and in combination with the armature and commutator thereof, a plurality of centrifugal I a elements arranged in groups ClICllIIiQIlQIltlal-Jfiitfffugdl elements ly and radiallylrelat ve tn the armature a spring element arranged circumferentially and operable radially with the centrifugal elements and adapted to exert resistance thereon at n angle to their said radial movewhereby pressure is provided for hinp wiping contact between said elements and the commutator s ort-circuiting mechanism for e, alternating current motors and with the armature and commutator thereof, a plurality ,of centrifugal elements arranged in equal groups, retained as to lateral displacement, and arranged circumferentially and radially relative to the armature shaft, and a spring element arranged circumferentially and operable radially with the centrifugal elements and adapted to exert resistance thereon at an angle to their said radial movement whereby pressure is provided for establishing wiping contact between said centrifugal elements and the commutator segments.

8. In short-circuiting mechanism for single-phase, alternating current motors and in combination with the armature and commutator thereof, a plurality of centrifugal elements arranged in equal groups, retained as to'lateral displacement by certain of the elements of each group, and arranged circumferentially and radially relative to the armature shaft, and a spring element arranged circumferentially and operable radially with the centrifugal elements and adapt-- ed to exert resistance thereon at an angle to their said radial movement whereby pressure is provided for establishing wiping contact between said centrifugal elements and the commutator segments.

4. In short-circuiting mechanism for single-phase, alternating current motors and in combination with the ai'niature and commutator thereof, a plurality of radial centrifugal elements arranged in equal groups circumferentially of the armature shaft and retained axially thereon by a disc having a series of raidal slots, certain of said elements being operable in said slots and acting to retain the elements of each group as to-latera l displa'cement thereof, and a'spring element arranged circumferentially and operable radially with the centrifugal elements and adapted to exert resistance thereon at an angle to their said radial movement whereby pressure is provided for cs tablishing wiping contact between said centrifugal elements and the commutator segments.

5. In short-circuiting mechanism for single-phase, alternating current meters and in combination with the armre and the commutatoL t'here of a plurality of radial arranged in equal groups circumferentially of the armature shaft and retained axially thereon by a disc rotatably supported on the armature shaft and having a series of radial slots, certain of said elements being operable in said slots and acting to retain the elements of each group as to lateral displacement thereof, and a spring element arranged circumferentially and operable radially with the centrifugal elements and adapted to exert resistance thereon t an angle to their said radial movement whereby pressure is provided for establishing wiping contact between said centrifugal elements and the commutator segments.

6. In short-circuiting mechanism for single-phase, alternating current motors and in combination with the armature and the commutator thereof, a plurality of radial, wedge-shaped centrifugal elements arranged in groups circumferentially of the armature shaft, and retained axially thereon by a disc mounted on said shaft and having a series of radial slots, other radial centrifugal elements interposed between the groups of the wedge-shaped elements and operable in said slots to retain the elements of each group as to lateral displacement thereof, and a spring element arran ed circumferentially and operable radial y with the centrifugal elements and adapted to exert resistance thereon at an angle to their said radial movement whereby pressure is provided for establishing wiping contact between said centrifugal clements and the commutator segments.

7. In a short circuitin device for electric motors, a rotor sha t, a commutator mounted thereon, a retaining member slidably mounted on said shaft adjacent to said commutator, means for limiting the movement of said retaining member away from said commutator, an annular series of centrifugal Weight members interposed between said commutator and said retaining member, operable radially to effect the short circuiting of the commutator, and a contractile band in rolling engagement with said weight members and arranged to simultane ously resist the outward movement of said weight members and .maintain them in resilient sliding contact with the commutator, and to maintain said retaining member yieldingly in engagement with the means for limiting its movement.

8. A short circuiting device for electric motors, comprising in combination with a shaft and a commutator carried thereby, said shaft having a circumferential groove spaced from the face of said commutator, a retaining disc mounted on said shaft between said groove and said commutator and having a series of radial slots spaced one from the other, a lock ring. seated in said groove and engaging said disc to limit the axial movement thereof with relation to said commutator, a series of weight elements mounted circumferenti-ally of said shaft between said disc and said commutator and movable outwardly by centrifugal force, a

part of said weight elements having projections slidably mounted in the respective slots in said disc, and a tension element acting on said weight elements to resist their outward movement and on said retaining disc to press the same against said lock ring.

9. Afishort circuiting device for electric motors, comprising in combination with a shaft and a commutator carried thereby, said shaft having a circumferential groove spaced from the face of said commutator, a retaining member mounted on said shaft be tween said groove and said commutator, a lock ring seatedin said groove and engaging said retaining member to limit the axial movement c thereof with relation to said shaft, a series of weight elements arranged circumferentially of said shaft between said retaining member and said commutator and movable outwardly by centrifugal force, and a tension element acting on said weight elements to resist their outward movement and on said retaining member to press the same against said lock ring.

10.'A short circuiting device for electric motors comprising in combination with a shaft and a commutator carried thereby, said shaft having a circumferential groove spaced from the face of said commutator, a retaining member mounted on said shaft between said groove and said commutator, a lock ring seated in said groove and engaging said retaining member to limit the axial movement thereof with relation to said shaft, a series of weight elements arranged circumferentially of said shaft between said retaining member and said commutator and movable outwardly by centrifugal force, said weight elements having their outer ends inclined toward said retaining member and said-shaft, and a contractile band engaging the inclined ends of said-weight elements and said retaining member to resist the outward movement of said weight elements and to press the same toward said commutator, and acting on said retaining member to press the same against said lock ring.

In testimony whereof, I afiix my signature.

GEORGE H. LELAND. 

